With the development of the times, the mobile phone positioning technology has drawn more and more attentions. However, all of the currently used positioning technologies, such as a Global Positioning System (GPS) positioning technology, a wireless sensor network-based positioning technology, or other positioning means, have their respective limits. In order to achieve higher positioning accuracy, combination of multiple positioning systems for cooperative positioning (also called multimode positioning) is a direction for future development. Multimode positioning can utilize advantages of various positioning methods to achieve higher positioning accuracy and response speed and also cover a wider range to implement seamless and accurate positioning.
For example, a satellite positioning system and a mobile communication system are organically combined for mobile phone positioning. Advantages of large coverage area and high open space positioning accuracy of the satellite positioning system and high indoor and dense urban area positioning accuracy of a mobile communication network are fully utilized, so that a market requirement is better met.
It is known that, as shown in FIG. 1 and FIG. 2, positioning with a satellite positioning system is implemented by finding at least four satellites, then performing distance measurement according to time of arrival, listing at least three spherical equations or hyperbolic equations according to distances and obtaining a current position for positioning in a manner of resolving the equations.
However, in an indoor circumstance or a dense urban area, a GPS signal is highly attenuated, so that four satellites may not be completely found, GPS positioning may not be implemented, and a positioning function is restricted.
Usually, a coverage environment of a cellular network in a dense urban area and an indoor condition is obviously superior to a satellite signal, but the problem of inaccuracy of cellular positioning exists because of factors of Non Line Of Sight (NLOS), multiple paths and the like. Regarding this problem, researchers in this field have obtained some research results, but these research results are obtained on the basis of ideal assumptions, and are industrially infeasible in terms of accurate positioning. Therefore, a feasible wireless positioning method capable of providing an accurate positioning capability during a practical application is urgent to be further deeply researched and provided.